Design and Implementation of UWB/MIMU Tightly-coupled System for Indoor Positioning

UWB (Ultra-wideband) technology is a very promising indoor positioning method because of the advantages of anti-multipath and high precision. For UWB positioning, at least three distance measurements between the base station and a mobile station are required. In practical applications, the signal loss of base stations often occurs due to occlusion and other factors, then resulting in the failure of positioning. To solve this problem, a tightly-coupled method which combines UWB range and measurements of MIMU (Micro Inertial Measurement Unit) is proposed in this paper. The integration positioning system can work continuously during the loss of UWB signals with advantages of INS (Inertial Navigation System) technology's autonomy and high precision in a short time. A tightly-coupled filter based on EKF (Extended Kalman Filter) is designed, and the integration system is implemented. The simulation based on Matlab and experiments in the indoor testing scene based on the Optitrack system are carried out respectively. The results show that the UWB/MIMU tightly-coupled system can solve the problem of positioning discontinuity caused by signal loss of UWB base stations, and the precision of dynamic positioning is better than 0.3 meters in complex indoor environments.